Wednesday, Mar 27, 2013
Small earthquakes have also been more frequent under and near the Askja caldera and Bardabunga volcano (to the SW of Askja) in the past few days. [more]
Sunday, Mar 10, 2013
A swarm of earthquakes at shallow depths, mostly around 2-5 km has been occurring in an area about 12 km NE of the caldera. 27 quakes including 6 between magnitudes 2.1-2.7 were recorded yesterday. [more]
Askja volcanoAskja is a large basaltic central volcano that forms the Dyngjufjöll massif. It is truncated by three overlapping calderas, the largest of which is 8 km wide and may have been produced primarily from subglacial ring-fracture eruptions rather than by subsidence.
Background:A major rhyolitic explosive eruption from Dyngjufjöll about 10,000 years ago was in part associated with the formation of Askja caldera. Many postglacial eruptions also occurred along the ring-fracture. A major explosive eruption on the SE caldera margin in 1875 was one of Iceland's largest during historical time. It resulted in the formation of a smaller 4.5-km-wide caldera, now filled by Öskjuvatn lake, that truncates the rim of the larger central caldera. The 100-km-long Askja fissure swarm, which includes the Sveinagja graben, is also related to the Askja volcanic system, as are several small shield volcanoes such as Kollatadyngja. Twentieth-century eruptions at Askja have produced lava flows from vents located mostly near Öskjuvatn lake.
Source: GVP, Smithsonian Institution